Direct current power supplies drawing primary energy from alternating current sources have been known for half a century. Such electric power supplies were first equipped with automatic regulating circuitry about forty years ago. Much work has been done in improving the regulation and in increasing the current regulated until the art is replete with excellent potential and/or current regulating circuitry. For a time, any loss due to the regulating circuitry was considered well spent. Much more recently, however, the attention of those skilled in the art has turned to reducing the loss brought about by the regulating circuitry to a very low minimum and, of course, conversely increasing the efficiency.